Glare light from a ceiling-mounted fixture, for example, is that which is emitted at angles close to the horizontal and which passes across the room and strikes the viewer's eyes, producing the sensation of glare. The light which creates such glare provides little useful light for any visual task being performed by the viewer. As a result, it is conventional to control the emission of light by screening means to restrict the output of light rays at angles close to the horizontal.
In the design of such screening means, it is desirable to absorb as little light as possible. Preferred designs redirect light rays traveling at high angles to lower angles where they emerge to form useful light beneath the lighting fixture.
Louver panels of various forms are frequently used as screening means and are well known in the art. They are normally placed beneath the lighting fixture to provide the desired screening.
One class of louver unit construction which is known performs the aforedescribed light redirection function by the use of curved surfaces formed on the sides of the louver blades and coated with specular aluminum. These blade surfaces intercept light rays emitted at a relatively high angle from the vertical and redirect them at a lower angle; i.e., more toward the vertical. As a result, the useful effect of the light rays is increased.
This type of louver unit is effective and has many advantages. However, it does have shortcomings in the area of uniform light distribution and appearance where non-symmetrical light fixtures are employed; i.e., elongated fluorescent fixtures, for example.